I’m a wine critic and author with 30 years of tasting and fieldwork experience. It was the changing taste of my favourite wines that brought me to climate change, I founded The Wine and Climate Institute in Oxford (www.twacci.org) in 2016, after having published my first book on wine and climate change in 2014. This blog contains extracts from my UN research, my talks, articles and books, and it is all about wine, climate change, freshwater management, the water and earth sciences, coastal and maritime cultures such as the Vikings and the Saami, Northern issues, Indigenous Knowledge Systems and TEK, etc. Basically, all things Water and anything else that interests me. My greatest hope is to be part of the solution.
Irrigation initially provides an increase in soil fertility and thus, increased yields. But excessive or long-term supplemental irrigation leads to soil salinisation and biological depletion and soil death. The great river civilisations were victims of this irony - of reaching their optimal productivity levels with the help of irrigation to then only decline due to this very success. The North American Hohokam tribe lived along the Salt River Valley in Arizona's hot and dry the Sonoran Desert 600-1600 years ago. Highly-sophisticated irrigation engineers, they created the greatest and most complex canal system, 1,500 kilometres (932 miles) of canals in the prehistoric Americas. Initially, this system worked and crop production was abundant. It was the accumulation of salts that damaged the soil and eventually killed the crops. Interestingly, there is evidence that they also farmed in areas away from the riverbanks, in purpose-built terraces that caught rainwater.
The occasional great floods could flush the salts out of the soil and allow them to gain a small reprieve, but such floods then caused other, insurmountable problems. It was their total reliance on river water irrigation that invited their downfall. Salinated soils and soil erosion due to irrigation are recurring themes throughout agriculture's history. There is solid evidence that the Mesopotamian civilisations along the Tigres and Euphrates flourished and then failed due to human-induced salinisation. After almost five thousand years of thriving irrigated agriculture, the Sumerian civilization failed.
The Mayans of Central America had a productive, sophisticated farming system that supported its major population growth. So to sustain this growth, crop cultivation encroached onto more marginal land, stressing the soil and water resources, which in turn created a more vulnerable system. The response was further intensification. They developed irrigation and agricultural technologies so to adapt and continue as long as possible, which only weakened the fragile ecological system further. Then there is the Viru Valley of Peru, the Indus Valley civilisation, and the Yellow River Valley … all have long been plagued by salinisation. In fact “historical records of the last 6,000 years show that civilized man, with few exceptions, has never been able to continue a progressive civilization in one locality for more than…800 to 2,000 years. And in most cases civilizations grew for a few hundred years, then declined or were forced onto new land” (Gelburd 1985). These cautionary tales echo today’s current ecological state of emergency, verbatim.
The lessons have not been learned. Soil salinity is still the greatest threat to agricultural productivity and sustainability. Shabir, Zaman, and Heng (see Sources page) report that statistics on salt-affected soils vary according to different data sources. But confirm that saline soils already occupied more than twenty per cent of the world’s irrigated area by the mid-1990s and that since then, the extent of salinity has likely increased. They assert that in some countries, salt-affected soils occur on more than half of the irrigated lands (2018).
The United States is the greatest offender of water waste. “In the western states, irrigation accounts for ninety per cent of total water consumption. Irrigated land increased from 4 million acres in 1890 to nearly 60 million in 1977, of which 50 million were in the arid western states. Irrigation waters contribute 500,000 to 700,000 tons of salt annually to the Colorado River: the loss of yield due to salt is estimated at $113 million a year. In San Joaquin Valley, California, there is an estimated loss of $312 million annually” (Shiva). These figures will have only increased as they are sourced from 2001. Shiva further asserts that with aquifer depletion, such as with the Ogallala Aquifer in Texas, which has between five and eight million acre-feet of water extracted annually, the only option left will be to transition “to water-prudent dryland farming or to abandon agriculture altogether” (2016).
LJB, Founder, The Wine and Climate Change Institute, www.twacci.org
